


Day Twenty-One

by FellQueen (Nikasha)



Series: Kinktober 2019 [20]
Category: Undertale (Video Game)
Genre: Cunnilingus, Face-Sitting, Lust sans - Freeform, M/M, Open Relationships, Underfell Sans (Undertale)
Language: English
Status: Completed
Published: 2019-10-22
Updated: 2019-10-22
Packaged: 2020-12-28 04:14:50
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,148
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21130592
Author URL: https://archiveofourown.org/users/Nikasha/pseuds/FellQueen
Summary: Day Twenty-OnePrompt: Face-sittingPairing: RedLight (Underfell!Sans/Lust!Sans)





	Day Twenty-One

**Author's Note:**

> I have no idea what the pairing is actually called, I made that up. Like RedLight District? Anyway.
> 
> I’m behind by 3 days oooooops. But it’s fucking midnight, take my shit and I shall sleep for now.

“Lust?” Red called out as he meandered from his shortcut point in the living room towards the kitchen. “Babe, where the fuck are you?”  
He had propped open the refrigerator door and was eyeing some leftover takeout, mustard bottle in hand, when he heard a soft, breathy noise. Curiosity instantly piqued, he shut the fridge and abandoned the mustard on the counter before heading back towards their room.  
The door was satisfyingly silent as it swing open and Red leered at the sight presented to him.  
Lust was spread out in the middle of their bed, jacket still hooked loosely around his elbows but the rest of his clothes somewhere across the floor. He had what looked like some type of dildo pressed almost completely inside him, gripping the base tightly with one hand while the other was scraping over his ribs. His eyes were shut and his mouth open with a tantalizing peek at a purple tongue that pressed against his teeth. The sweep of color across his face was charming.  
Red felt his magic race southward. Not really surprising whenever he was around this monster.  
He took careful, noiseless steps towards the bed until he was standing over Lust, hands folded in his pockets and probably grinning savagely. His gaze slid to Lust’s pelvis as he slid the toy out and pushed it back in, huffing.  
“That’s hot,” he said, loudly and abruptly.  
Lust startled, jumping visibly as his sockets flashed open, heart-shaped lights focusing on Red. He chuckled shakily, relaxing back into the bed. “Fuck, cutie, give a guy some warning!”  
“Hmm.” Red leaned in to kiss him and enjoyed the happy purr it got from Lust. “I’ll consider it.”  
Lust rolled his lights. He started pressing his legs together uncomfortably and gave Red his patent puppydog pout. “Baby, I need something bigger inside me. Help a girl out?”  
“All you needed to do was ask,” Red growled, reaching down to take the dildo from Lust’s fingers. He pulled it out completely, tossing it to the floor.  
“Ew, Red!” Lust gasped, insulted. “Now it’s gonna have hair and dirt and shit on it.”  
“Neither of us have hair to shed, get your panties out of a twist.” He climbed onto the mattress, looming over Lust with his sharp-toothed grin. “Just clean it later, you freak.”  
Lust shivered, but put a hand on Red’s shoulder. “Hold up, I wanna be on top.”  
Red’s eyes flashed momentarily, but the spike of hesitation faded to curiosity. “If you ask nicely, may—“  
“Please?” Lust made his eyelights blow wide, holding his delicate hands up to his mouth prettily. “I’ll suck your dick, daddy~”  
Red winced and rolled over out of the way. “You know I don’t do that kink.”  
Lust snickered as he sat up, waiting for Red to lay down, then turning to straddle him. “Oh, I know, sweetie. You just make such a fantastic face when I say it out of nowhere.”  
“Bitch,” Red said affectionately, hands settling on Lust’s hips. Lust kissed him and they were preoccupied for a moment just battling with their tongues. Then Red scraped Lust’s coccyx and he gasped, arching his back sharply. Red started to tug at his shorts to free his cock when Lust shifted forward and moved up his body until he was straddling Red’s face, hands braced on the headboard. “Good?” he asked pleasantly.  
Red growled and used his grip on Lust’s hips to pull him down, hungrily licking up the liquids already pooling from Lust’s cunt.  
Lust sighed, shifting a little to get more comfortable. “Oh, babe, you’re so good.”  
Red grunted in agreement then drew his tongue across Lust’s clit in a hard swipe, earning a whimper. He did it again and, smelling Lust’s arousal leaking from him again, shifted to bury his tongue deep inside Lust’s entrance.  
“Fuck,” Lust sighed, tossing his head back.  
Red was pleased with himself and content to play with him like that when he felt Lust shift his weight again and sink down. With his cunt completely pressed to Red’s face, it was suddenly hard to breathe but he wasn’t complaining. Red rumbled, nuzzling Lust’s clit with the blunt side of his nasal bone, digging further in with his tongue then drawing back out to swallow the slick on his tongue.  
Red worked him over, plying all the tricks he knew. Lust was too experienced to be satisfied with anything less than his best effort. Finally, when he was mildly dizzy from the heat and stimulation of ingesting a bit of Lust’s magic, he felt his lover shuddering under his grip. He growled again, sharp fingertips digging into bone and he viciously licked.  
“Fuck!”  
Red reveled in it as Lust fell apart, swallowing down his magic greedily. He licked across and inside him for the remnants until Lust grabbed his hands, hissing at the overstimulation. He wasn’t saying to stop, but Red did, letting go so Lust could move away and give him space. He sucked in a breath then licked his teeth, staring at Lust.  
The other monster smiled, wiping a mark of purple off of his cheek. “Missed some, babe.”  
Red was happy to lick it off his fingers, needling the tips with his sharp teeth.  
Lust moved back and aligned their hips, freeing Red’s dick and running his hands over it in practiced sweeps that had the red skeleton twitching. As Lust lined him up with his cunt and sank down, he asked, “So how was it?”  
Red barked a laugh. Lust always wanted to chat while fucking, it was the funniest shit. “The party? Dope. No one dusted, though, that was a bit of a bummer.”  
Lust rolled his eyelights along with his hips, hands bracing on Red’s ribcage. “Dying, everyone’s favorite at a rave.”  
Red thrust up into him to see him jolt and throw off his rhythm. “Yeah, yeah. Tell me again why you didn’t go?”  
Lust broke into a wide grin. “Mettaton was having an orgy, duh! I didn’t see my brother, not sure where he was, but Asgore was there and unf.” He paused to fan himself. “That dick, babe. I thought my back was gonna break.”  
Red snorted loudly, amused. “Did you play by the rules?”  
Lust got a surprisingly gentle look to his face, resuming his rocking motions. “Of course. No one hurt me, no one put any mark on me. Here...” He tugged completely free of his jacket, tossing it away and spreading his arms. “You can check for yourself.”  
Red sat up, one hand propping himself up while the other rested on Lust’s femur. He gave him a thorough lookover as best he could from this position, then pressed their teeth together. “You may be a freak, but you’re a good freak.”  
Lust laughed. “Flattery. Now lay down and let me fuck you.”  
Red was happy to oblige.

**Author's Note:**

> List used: https://twitter.com/idek_uggy/status/1178349575725174786?s=21
> 
> Tomorrow is cuckolding, but I’m switching to either fear play or shotgunning, not decided yet.


End file.
